The present invention generally relates to communication systems. More specifically, the invention relates to techniques to perform sub-picture level splicing based on interrupts.
Over the past few years, the television industry has seen a transformation in a variety of techniques by which its programming is distributed to consumers. Cable television systems are doubling or even tripling system bandwidth with the migration to hybrid fiber coax (HFC) cable plant. Direct broadcast satellite (DBS) systems have also emerged as a viable alternative to customers unwilling to subscribe to local cable systems. A variety of other approaches have also been attempted, which focus primarily on high bandwidth digital technologies, intelligent two-way set top terminals, or other methods to try to offer services differentiated from those of standard cable and over-the-air broadcast systems.
With the increase in bandwidth, the number of programming choices has also increased. Leveraging off the availability of more intelligent set top terminals (STTs), several companies have developed elaborate systems for providing an interactive listing of a vast array of channel offerings, expanded textual information about individual programs, and the ability to look forward as much as several weeks in advance to plan television viewing.
Unfortunately, the existing program guides have several drawbacks. First, these guides tend to require a significant amount of memory at the set top terminal. Second, the terminals may be very slow to acquire the current database of programming information when they are turned on for the first time or are subsequently restarted (e.g., a large database may be downloaded to a terminal using only a vertical blanking interval (VBI) data insertion technique). Such slow database acquisition may disadvantageously result in out of date information or, in the case of services such as pay-per-view (PPV) or video-on-demand (VOD), limited scheduling flexibility for the information provider. Third, the user interface of existing program guides do not usually look like a typical television control interface; rather the user interface looks like a 1980's style computer display (i.e., having blocky, ill-formed text and/or graphics).
An improved interactive program guide (IPG) system has been developed, which partitions guide pages into a number of regions, each of which may be individually encoded as slices and transmitted via a respective packet identifier (PID). This encoding scheme reduces the amount of redundant data transmitted for the guide pages. At the terminal, slices for the various regions are recombined (i.e., spliced) to form the desired guide page. Because a number of splices may be performed for a picture of a guide page, techniques that facilitate and improve the splicing process are highly desirable.